This invention relates to a beverage apparatus suitable for use in a beverage vending machine, and more particularly, to improvement of the sealing situation between the brewing cylinder and brewing cavity during the extracting operation of the apparatus.
Beverage brewing apparatus suitable for use in vending machines for preparing single cup quantities of beverages from beverage material is well known in the prior art. For example, U.S. Pat. No. 3,349,690 issued to William Heier discloses one construction for such a brewing apparatus.
Referring to FIG. 1 on the application drawings, the basic construction and brewing cycle of a prior art apparatus will be described. Frame 1 of the apparatus supports a vertically movable open-bottom cylinder 2 which has the bottom opening covered by a filter member 3. A vertically movable piston 4 is disposed within cylinder 2 and relative movement between cylinder 2 and piston 4 is created by operation of a cam member 5 driven by motor 6. One end opening of a duct 7 is connected with a water tank (not shown) through electromagnetic valve 9, this end opening being closely placed above the upper opening of cylinder 2 to supply hot water into cylinder 2. A brewing cavity 10, which is generally reciprocable horizontally to a brewing position (this position being shown by solid lines in FIG. 1), is placed beneath the cylinder 2 and sealed with the lower portion of cylinder 2 in the brewing position.
In this apparatus, brewing cavity 10, at the start of a brewing cycle initiated by a coin operated switch for example, moves horizontally toward the brewing position from the rest position to be placed beneath the bottom opening of cylinder 2. During this horizontal movement, ground coffee is supplied into the brewing cavity 10 through coffee hopper 11 at a supply position (this position being indicated by dotted lines in FIG. 1). When brewing cavity 10 is properly aligned beneath the cylinder 2, due to the operation of cam member 5, cylinder 2 moves downwardly into tight engagement with cavity 10. This forms a chamber which is filled with hot water supplied through duct 7.
Thereafter, piston 4 moves downwardly to force the water through the filter member 3 into the ground coffee in cavity 10 and through an outlet conduct 13 to a cup 14 placed at a dispensing station. Before introducing coffee into the cup, the extracted coffee would be mixed with a suitable amount of sugar and/or cream, both of which are supplied from canisters 15 and 16, respectively. Thereafter, the brewing cavity 10 containing the spent coffee grounds is moved to its rest position. The grounds in the brewing cavity 10 are discarded at a position which is disposed just before the rest position is reached. When the brewing cavity 10 is returned to its rest position, one brewing cycle has been completed.
In the above described apparatus, brewing cavity 10 is normally moved by operation of cam member 5 acting through a cable, and engagement between cylinder 2 and brewing cavity 10 is done in the following manner:
(1) Initially, the brewing cavity is moved over to be beneath the position of cylinder 2, and thus put in its predetermined brewing position; PA1 (2) during the above mentioned motion of the cavity cylinder 2 is moved downwardly and before engaging with the cavity, a pair of pins formed on the lower end surface of cylinder 2 engage with the outer peripheral edge of cavity 10; PA1 (3) then, the relationship between the cylinder and cavity is determined by engagement of the pins and cavity and tight sealing between the cylinder and cavity is secured.
However, the required relative movement between the cavity and the cylinder is a critical operation. Since the range of engagement between the pins and the cavity is very limited if the movement of either one of the cavity or cylinder goes wrong which may be caused by dimensional error or timing change, the precise engagement between the cylinder and cavity is destroyed. Thus, the sealing between the cylinder and cavity is improper. Also, even if the engagement between the cylinder and cavity is previously set at the initial state, the engagement position may become offset from its intended predetermined position by increasing length of the operating cable caused by long time usage of the apparatus.